In the field of chemical and physical filtration, both flotation and sedimentation are used. Here, both the chemical and physical components from LK are customised.
Flocculation is a process in which dispersed by means of gas bubbles in the liquid particles (solid particles, droplets, molecules, ions) aggregates are formed, which are then, due to the lower density than the surrounding medium, rise to the liquid surface and form a detachable foam layer. In foam product, the floatation items lie above the intended particles. The buoyancy of the substances to be separated is increased artificially by the addition of fine air bubbles. The resulting supernatant solid foam (Flotat) is withdrawn.
Precipitation is a chemical process for converting dissolved compounds in an unresolved state by adding suitable chemicals. The resultant precipitation product can then be separated by appropriate physical processes (e.g. as sedimentation, flotation, filtration). Precipitation treatments as practiced for example for the separation of phosphates. Precipitation reactions also be applied for particularly the separation of dissolved metal ions. The most common precipitating form is the conversion into sparingly soluble metal hydroxides. It can also be reduced by precipitation in certain cases, after the biological treatment continues in the sewage remaining organic residue harmfulness (residual COD).